Wall-type fuel burning heater



Oct. 11, 1949. H. A. MARBLE WALL-TYPE FUEL BURNING HEATER Filed Dec. 22. 1947 2 Sheets-Sheet 1 ATTORNEYS Oct. 11, 1949. A. MARBLE 2,484,457

WALL-TYPE'FUEL BURNING HEATER Filed nec. 22, 1947 2 sheets-sheet 2 FIE..

PIE 4 INVENTOR Haro/d f4. Marb /e BY ATTORNEYS Patented Oct. 11, 1949 WALL-TYPE FUEL BURNING HEATER Harold A. Marble, Millbrae, Calif., assignor to International Sales Company, San Francisco, Calif., a corporation of California Application December 22, 1947, Serial No. 793,173

3 Claims.

This invention relates generally to the construction of room heaters of the so-called wall type.

In the past it has been common to construct relatively compact gas heaters adapted to be installed in a wall recess, and arranged to connect with `a flue pipe which is likewise concealed within the wall. A grill extends over the front of the heater whereby air from the room circulates into and out of the grill in heat transfer relationship with a suitable heating unit.

Room heaters of the above type, such as have been made in the past, have been subject to certain disadvantages. Particularly the flue pipe into which the hot `gaseous products of combustion are discharged' tends to be heated to a relatively high temperature, thus causing a lire hazard. This is due to the relatively high temperature of the gaseous products of combustion leaving the heating unit. In addition the back wall of the heater housing tends to be heated to a relatively high temperature, due to absorption of heat from the heating unit.

It is an object of the present invention to provide a wall type of room heater which avoids heating of the associated flue pipe to an unduly high temperature.

Another object of the invention is to provide a heater of the above type having provision for more adequate cooling of the back wall of the housing.

Further objects of the invention will appear from the following description in which the preferred embodiment has been set forth in detail, in conjunction with the accompanying drawing.

Referring to the drawing:

Figure 1 is a front View, with the grill removed, showing a gas heater incorporating the present invention.

Figure 2 is a cross-sectional view taken along L' the line 2--2 of Figure 1.

Figure 3 is a cross-sectional View taken along the line 3-3 of Figure 1.

Figure 4 is a cross-sectional view taken along the line 4--4 of Figure 1.

Referring first to Figures 1 and 2, my heater consists of a sheet metal housing I0, which is adapted to be tted into the wall recess I l. The front side of the housing is covered by the grill l2, which consists of the upper part I2a, the intermediate part 12b, and the lower part l2c.

Within the housing there is a heater unit I3 which may vary as to details of construction. The particular unit illustrated consists of a lower fire box I4, which is provided with fuel burners I6. Heat exchange tubes I1 extend upwardly from the re box I4, and are connected at their upper ends to the ue box I8. The flue box may be of conventional construction, and is shown provided with the inclined baille wall I9, having a slot 2| for passage of products of combustion. The iront side 22 of this box, above the baffle I9, is open through the grill.

The heating unit I3 is surrounded on three sides by baffle walls, including the vertical back wall 23, and the vertical side walls 24 (see Figure 4) An additional vertical balile wall 26 is mounted in spaced relationship with the Wall 23.

At the upper end of the wall recess there is a plate 21, which extends completely across the recess, and which is attached to the wall studding. A short conduit 28 is carried by the plate 21, and communicates through the same. Conduit 28 ts within the lower portion of the regular flue pipe 29, which is generally made of suitable refractory material, and which extends upwardly through the wall to a point of discharge.

Extending upwardly from the wall 3l of the flue box I8, there is a conduit 32 which is considerably smaller than the conduit 28. It will be noted that when installed, conduit 32 extends upwardly through the conduit 28, leaving a space or passage 33 for flow of air. Passage 33 communicates with the connected passages 34 and 36, the latter having a lower open end communicating with the space 31 between the baille wall 23 and the back housing wall 38. Passage 34 is dened by the sheet metal wall 39, which underlies the plate 21, and by the vertical wall 42,

f' `which extends between and is spaced from baille wall 23 and the back housing wall 38.

Operation of the heater described above is as follows: Before installing the heater the lower end of the flue pipe 29 is iitted with conduit 28, and the plate 21 is suitably attached to the adjacent studding. When the heater is placed in the wall recess, care is taken to introduce the conduit 32 through the conduit 28, and to t the upper part of the heater housing about the plate 21 in the manner illustrated in Figure 2. When the heater is in use, air from the room will circulate into and out of the housing through the front grill. Convection currents of air entering the lower part of the heater housing flow in part upwardly through the passage 31, and part of this air enters the passage 36, and discharges through the passage 33 into the flue 29. Gaseous products of combustion at an elevated temperature are discharged from the flue box I8, through the conduit 32, and into the nue pipe 29. The hot gases 3 discharging from the upper end of the conduit 32 intermingle with the much cooler air being delivered through the passage 33, and therefore as a result the temperature of the products of combustion is immediately lowered to prevent undue heating of the ue pipe.

In addition to effectively reducing the ternperature of the flue pipe 29, the temperature of the back wall of the heater is materially reduced. This is due to the increased upward circulation of air from the room through the passage 31, which is induced by the iiow of air through the passages 35, 34 and 33. It is also due in part to the location of the passage forming wall 42. A decrease in the dew point of the gases in the flue 29 also takes place, thereby allowing a lower flue temperature Without condensation occurring.

The heater is not critical with respect to the point at which passage 36 communicates with the housing of the heater. However it may be desirable that wall 42 extend downwardly beyond the middle of the heater, thus receiving air which is reasonably cool, and also enabling it to serve as a heat baille.

l claim:

l. In a heater construction of the fuel burning type suitable for mounting in a wall recess and adapted to be connected with a nue pipe extending upwardly within the Wall from the recess, an outer metal housing adapted to t the recess, a grill extending over the front of the housing, a heating unit enclosed within the housing to heat air circulating through the grill and the housing, said heating unit including a lower fire box provided with a fuel burner and an upper flue box in communication with the fire box, a conduit communicating with the upper end of the hous ing and adapted to be tted into the lower end of the iiue pipe, a second conduit communicating with the ue box and extending upwardly through the rst named conduit to discharge into the flue pipe, the second conduit being or" smaller diameter than the nrst named conduit to provide a passage therebetween, and means for directing a part of the air circulating through the housing into said passage.

2. A heater as in claim 1 in which said last named means includes a baille Wall disposed between the heating unit and the back wall of the ill 4 housing, and providing with the back wall a vertically extending passage communicating at its upper end with said passage, and open at its lower end to receive air from the room.

3. In a heater construction of the fuel burning type suitable for mounting in a wall recess and adapted to be connected with a ue pipe extending upwardly within the wall from the recess, an outer metal housing comprising vertical side and back walls adapted to nt Within the recess, a grill extending over the front of the housing and permitting air from the room to circulate through the housing, a heating unit enclosed within the housing to heat air circulating through the same, said heating unit including a lower re box provided wit'h a fuel burner and an upper flue box in communication with the fire box, a vertical baiile wall disposed behind the heating unit and spaced with respect to the vertical back wall of the housing, a conduit communicating with the upper end of the housing and adapted to be fitted into the lower end of the ue pipe, la second 'conduit communicating with the flue box and extending upwardly through the rst named conduit to discharge products of combustion into the flue pipe, the second conduit being smaller in diameter than the irst named conduit to provide a passage therebetween, and walls serving to form a passage extending upwardly from the space between said baflie wall and the back wall of the housing and serving to deliver air into said passage between said conduits whereby air is caused to intermingle with the products of com- V bustion in the iiue pipe.

HAROLD A. MARBLE.

REFERENCES CITED The following references are of record in the fil-e of this patent:

UNITED STATES PATENTS Number Name Date 1,660,690 Terry Feb. 28, 1928 2,163,928 Andrews June 27, 1939 2,360,611 Leonard Oct. 17, 1944 FOREGN PATENTS Number Country Date 429,897 Great .Britain June 7, 1935 

